In the history of abortion politics, it was a key event: the 1992 move by Democrats to deny Pennsylvania Gov. Robert Casey Sr., an opponent of abortion rights, a speaking spot at the party’s national convention that year. Bill Clinton, of course, won that presidential election, but the move barring Casey, a Democrat who hadn’t endorsed Clinton, is widely seen as having alienated millions of religious abortion opponents who felt the party no longer had a place for them. This year the party is trying to change that perception, in line with other attempts to woo religious voters who in recent years have voted Republican by large margins. Casey’s like-minded son, U.S. Sen. Bob Casey Jr., D-Pa., an early supporter of presumptive nominee Barack Obama, is being given a speaking slot at the upcoming Democratic National Convention. And the party’s platform committee last week approved language that some liberal opponents of abortion say could draw back at least some of the alienated.